She says, ‘So if they’re not taking things to the next level, which they’re not, because Liv won’t, then the most opposite it could be to the break-up lie is same old, same old: they’re still having an affair. In which case, what changed to make them want to pretend to split up? I’m not expecting you to know, by the way. I keep thinking if I ask myself the same question for the millionth time, I might come up with the right answer. My starting point has always been that there’s only so many things a person might conceivably want to hide: infidelity, a drug habit, alcoholism, a secret life as an escort or a porn star, a second identity, an embarrassing illness …’

She mutters something I can’t make out. Then she says: ‘Nikhil and Natalie have got to be the key, right? They and Liv and Gibbs aren’t just normal friends. They’re … involved in something together, some business or arrangement.’

‘If your sister won’t leave her husband to move in with Gibbs, what about a baby? Could she be pregnant with his kid? Maybe … okay, this is far-fetched, but maybe Nikhil and Natalie are going to adopt it?’ I want to argue with myself already. ‘No, because how’s Liv going to hide a pregnancy from her husband? She’d be more likely to pass the kid off as his, wouldn’t she?’

‘Liv can’t get pregnant. She’s had ovarian cancer. The treatment left her infertile.’ Charlie sounds excited. She reaches for the Marlboro packet again. ‘Hang on – let’s not rule this out too quickly.’ The more interested she is in the conversation we’re having, the more she smokes. She ought to go on a road trip with Liam; she’d have clean lungs by the end of it.

‘Liv and Dom aren’t short of money …’ she murmurs.

‘So?’

‘I’m thinking surrogacy.’

‘What?’ Have I missed a stage?

‘Liv can’t conceive. She and Gibbs are in love, they want to make a baby together. That’s something most people in love want, right?’

‘Apparently. I don’t get it myself.’

‘Me neither, but we’re not typical, I don’t think.’

I file away that ‘we’ to mull over later. ‘Wouldn’t Liv want a baby with her husband if she wanted one at all?’

‘No. Liv loves Dom like a … big old sheepdog. A sheepdog who gets a million-quid bonus every year. She’s in love with Gibbs: he’s the one whose kid she’d want – but she can’t because she can’t get pregnant, so …’ Charlie shrugs. ‘It’s too ridiculous.’

‘So she takes some of her husband’s money, hires Natalie to be artificially impregnated by Gibbs?’

‘Something like that, yes. Don’t you think it’s possible?’